Wrap post thumbnail in custom field link

featured-image-link.php

<?php

if ( function_exists('has_post_thumbnail') && has_post_thumbnail() ) {
  echo '<a href="<?php echo tribe_get_custom_field('Label For Custom Field Link'); ?>">;
  the_post_thumbnail();
  echo '</a>';
}

?>

<?php if ( function_exists('has_post_thumbnail') && has_post_thumbnail() ) : ?>
    <a href="<?php echo get_post_custom_values('img_link'); ?>"><?php the_post_thumbnail(); ?></a>
<?php endif; ?>